Electromagnetic relay or switch



Feb 2, 1954 B. s. BENGTssoN l 2,668,207

ELECTROMAGNETIC RELAY OR SWITCH Filed July 22, 1949 2 Sheets-Sheet 1 j/o 64 ma #4162745 Feb, 2, 1954 B, s. BENGTSSON ELECTROMAGNETIC RELAY 0RSWITCH Filed July 22, 1949 2 Sheets-Sheet 2 g vw a/rvboz 55H 77m S.EEA/GTJSON Patented Feb. 2, 1954 ELECTROMAGNETIC RELAY OR SWITCH BortlS. Bengtsson, Hartford, Conn., assigner to The Hart ManufacturingCompany, Hartford. Conn., a corporation of Connecticut Application July22, 1949, Serial No. 106,138

7 Claims. l

This invention relates to improvements in electro-magnetic relays orswitches and, more particularly, but without restriction thereto, tosuch relays or switches which are hermetically sealed. Also, thisinvention readily lends itself to being embodied in very compact andsocalled miniature type relay and switch arrangements of the typefrequently used in various kinds of aircraft installations requiringrelay devices.

It vis an object of the invention to provide a multi-unit type relay inwhich the armature supporting means are adjustable and some of the polepieces are so constructed that, when the coil of the solenoid isenergized, the armatures respectively associated with said pole pieceswill be attracted toward other pole pieces in a predetermined sequence,which sequence may be varied by suitable adjustment.

It is another object of the present invention to provide a relay typeswitch construction including a base which may be sealed within the openend of a cup-shaped housing which may be used to hermetically enclosethe relay construction, the base directly supporting, in electricallyinsulated relationship, a plurality of conductor members to the innerends of which stationary contacts are directly connected, whereby no admditional conductors such as soldered flexible leads are necessarybetween the contacts and the conductors carried by the base for purposesof conducting current between the stationary contacts within thehermetically sealed housing and the exterior thereof.

A further object of the invention is to provide a very compactarrangement of pole pieces and an armature operated thereby, thearmature carrying a movable Contact assembly so constructed that it hasa plurality of contact fingers which permit yieldably and wipingengagement of several movable contact members with the stationarycontact to insure firm and clean electrical engagement between thecontacts.

'As a corollary to the foregoing object, it is a still further object ofthe invention to provide on the armature a longitudinally extendingflexible tail which is disposed for compactness along the coil of thesolenoid, the free end of the tail being adjustable toward and away fromthe solenoid to vary the force exerted by the flexible member to resistmovement of the armature toward its associated pole piece.

A still further corollary to said foregoing object is the furtherprovision of simple and unique means for mounting the armature and itsflexible tail member so that the latter comprises a hinge for thearmature, the tail member also including positioning means foroperatively positioning the armature and its tail member relative to itssupporting means so as to minimize assembly operations.

Still other objects of the invention are the construction andarrangement of the various components of the relay which results in avery compact, rugged and durable arrangement which may be hermeticallysealed, if desired, and used in situations where minimum size. weight,and contact resistance are desired as well as where the relays are to besubjected to extreme limits of shock, temperature and other physical andelectrical conditions. Further, the design of the components is suchthat the assembly thereof is greatly simplified as compared to presentlyused relays, whereby the cost of production is minimized.

Details oi these objects and of the invention, as well as other objectsthereof, are set forth in the following specification and illustrated inthe accompanying drawings forming a part thereof.

In the drawings- Figure l is a side elevation of a hermetically sealedmultiple relay switch unit embodying the principles of the presentinvention.

Fig. 2 is an enlarged, longitudinal, sectional view of the relay switchshown in Fig. 1.

Fig. 3 is a sectional, plan view taken on the line 3-3 of Fig. 2.

Fig. 4 is a sectional, 'plan View taken on the line 4-14 of Fig. 2.

Fig. 5 is a side elevation of the construction shown in Fig. 2, exceptthat only the housing is shown in section in Fig. 5.

Fig. 6 is an exploded, perspective view of the armature assemblyillustrated otherwise in Figs. 2 and 5.

Fig. 7 is a further enlarged, longitudinal, sectional View of anarmature assembly such as i1- lustrated in Figs. 2 and 5.

Referring to the drawings, a multiple switch type relay has beenillustrated for purposes of convenience, but it is to be understood thatthe specific number of relay switch units illustrated herein is notrestrictive since the construction is capable of operation when either asingle relay switch unit or a number of such units other than the numberillustrated herein are used.

The relay switch construction illustrated herein comprises a housing Illwhich is illustrated as being cup-shaped. The housing may be formed ofany impervious suitable material, such as metal, so that it may retainin its interior either an evacuated or gas filled atmosphere.

Sealed within the open end of the cup-shaped housing II! is a compositebase I2. In the present illustration. the base and housing have beenillustrated as circular in cross section, but it is to be understoodthat this'shape may be varied if and as desired. The base I 2 comprisesa cylindrical enclosing ring or band I4 within which a pair of parallelelectrical insulation plates or disks IG and IB are mounted in spacedrelationship. Said disks may be formed, for example. from mica, and areprovided with a plurality of transversely extending and alignedapertures 2U and 22, aligned pairs of said apertures receiving elongatedterminal conductors 24. Said conductors are provided intermediately oftheir ends with annular anges 26.

Disposed within the space between the disks IS and I8 and on oppositesides of the iianges 26 of the conductors are a pair of flexibleinsulating disks 28 and 3U which are apertured similarly to the disks i6and I8 for purposes o1' receiving the conductors 24. The disks 28 and 38are not only flexible but are yieldable and may be formed of anysuitable material, such as rubber, in order that. when the rigid disksI6 and I8 as well as the flexible disks 28 and 3D are disposed onopposite sides of the anges 26 of the conductors 24 within the band I4,the rigid disks I6 and I8 may be moved toward each other so as tocompress the flexible, yieldable disks 28 and 3!! around the flanges 26so as to seal the conductors 24 relative to the various laminated disksand thus prevent the passage of gas therethrough as well as electricallyinsulate the various conductors 24 relative to each other.

When forming the composite base I 2, the various conductors 24, rigiddisks I 8 and I 8, and flexible disks 28 and 3i! are assembled in theirproper relationship on opposite sides of the 'flanges 28 of theconductors 24 and all of said disks are compressed from opposite sidesof disks I'S and I8 while assembled within the band I4. The band ispreferably provided initially at one end with an annular flange 32 and,after the disks have been compressed, the other end of the band is spunor bent radially inward to provide another annular flange 34, wherebythe flanges 32 and 34 serve to maintain the various disks of the base incompressed laminated condition and said disks will not only support theconductors in operative and electrically insulated condition, but alsoin hermetcally sealed condition relative to the base as well.

The invention also contemplates mounting directly on the inner ends ofcertain of the conductors 24 stationary contacts 36 and 38. There isprovided, in the present illustrative embodiment of thek invention, apair of stationary contacts 36 and 38 for each relay switch unit. saidunits being indicated A, B, C, D, E and F in Fig. 4, each unit beingincluded within a bracket, and further details thereof are explainedhereinafter,

Such direct mounting of the stationary contacts 38 and 38 results inextreme compactness and saving of space as well as the elimination ofany electrical connecting means, such as short lengths of wire, whichwould require soldering at opposite ends to the conductors 24 andcontacts 35 and 38.

Such direct connecting of the conductors and contacts is effected, forexample, by providing the inner end of said certain stationary contactconductors with frusto-conical ends 40 which are outwardly. Thestationary contacts 36 and 38 are initially formed so as to becup-shaped and are placed over the ends 40 of the conductors. The rimsof the cup-shaped contacts are then swaged or otherwise shrunken so asto tightly adhere to the ends 40, whereby the contacts 36 and 38 andconductors are united in fixed relationship. The contacts 36 and 38 arepreferably formed from silver or silver alloy, which material readilylends itself to being secured in the foregoingmanner to the ends 48 ofthe conductors.

This arrangement permits the use of larger contacts than is frequentlypossible, particularly in small miniature relay units, whereby largeramperage loads may be imposed upon such relay switches for long periodsof use of the switch without requiring replacement of such contactsthrough deterioration resulting from arcing. Such arrangement alsoaffords another advantage in that, when certain portions of the exteriorcylindrical surface of the contacts 36 and 38 become worn due to arcing,the contacts may be adjusted to present a. new operating surface bymerely rotating the conductors 24 slightly about their longitudinalaxis, such rotation being effected by turning the outer ends of saidconductors about their axes.

The outer end of each conductor 24 extends from the exterior side of thebase I2 and said ends may be either electrically connected to a suitablecircuit by inserting the ends of the conductors 24 in a jack formed toaccommodate the same, or said outer end of each conductor may beconnected to a circuit by merely soldering or otherwise aflixing wiresof the circuit directly to said outer ends,

Extending perpendicularly from the surface of base I2 from which thecontacts 3B and 38 project is a mounting post or pin 42 which terminatesat one end in a transverse annular flange 44 disposed within the spacebetween the insulating disks It and I8. The end of said pin 42 adjacentthe flange 44 is preferably straight knurled as shown at 48 so as toprevent rotation of the pin 42 relative to the base and, in addition,the friction existing between the opposite surfaces of the flange 44 andthe inner surfaces of the disks i6 and I8 serves to do likewise.Surrounding said pin 42 adjacent the disk IB is a bushing 48. Alsodisposed on said pin 42 is a series of nested, concentric, tubularmembers formed from iron or steel and comprising a core 50. If desired,the ends of said tubular members nearest the base may be disposed withina recess 52 provided in one end of the bushing 48 which centers themembers of core 58 relative to pin 42.

Surrounding the end of the core 58 adjacent the bushing 48 is a set ofsimilar, laminated, iron or steel members 54 which are provided witheircumferentially spaced radial notches to provide a plurality ofcircumferentially spaced, radially projecting pole pieces 56.Surrounding said core 50 between the pole pieces 56 and the outer end ofthe core ,is a coil 58 mounted on a suitable 'anged spool Sil. Abuttingthe outer end of the core E0 and mounted adjacent the outer end of Din42 is another pole piece member' 52 provided with a series ofcircumferentially spaced pole arms 54 which extend radially therefromior a short distance and are then bent substantially at aright angle soas to extend parallel to the core 50 toward the pole pieces The portionsof the pole arms Si; which are parallel to the core comprise pole piecesGli. A washer 5l of 10 any suitable compressible material such assiliconc rubber is disposed in the bottom ol recess 52 to urge thetubular members of core 5% into rm engagement With pole piece member G2.

For purposes of convenience in description. the l5 ipole pieces 5G aredesignated n rst pole pieces and pole pieces 55 are designated secondpole pieces. The pole pieces each terminate in an ond surface 68, saidend surfaces all being in comincio plane perpendicular to the pin l2 andsaid plane 20 beingr spaced a short distance away from. but

rlongitudinally aligned with, the pole pieces 5o.

Each pair of longitudinally aligned pole pieces 5B and 56 is providedwith an armature assembly generally designated lil and illustrated indetails 25 in Figs. 6 and 7. Each armature assembly coin- Drises an ironor steel armature bloei:` l2, one end of which is disposed against theend (is of the first pole piece et. The lirst pole pieces 66 thus serveto dispose the pivot point of 30 armature assemblies 'lll close to thesecond pole pieces 55. The armature block l2 is connected for limitedpivotal movement relative to said end surface 6% by means of anelongated hinge member lil. One end of said hinge inembe is 35 connectedto the armature block 'l2 and extends Van appreciable distance beyondthe armature in one direction so as'to overlie but, at its outer end, besomewhat spaced from the rst pole piece G6. The hinge member l!! may beforni rom any suitable resilient material such, for e.- ample, asberyllium-copper;

Projecting in the same direction from opposite side edges of the hingemember 'M intermediate the ends thereof are a pair of parallel ilanges'it Ai3 which are disposed Within a pair of compleinciitary elongatednotches 'l formed in opposite side edges of the rst pole piece lili,whereby said flanges "I6 serve to position the arma-ture assemblyconnected to the hinge member rclaive to such first pole piece Theflanges '15, by being received within the elongated notches 78, willprevent longitudinal movement ci the armature assembly relative to thefirst pole piece `66 and also prevent movement of the armature assemblyrelative to its first pole piece Sli in directions tangential to thecoil 58.

Secured adjacent the pole piece engaging surface of each armature block'l2 is a shock absorbing member Elie which is preferably for-ined troni5i non-magnetic material for purposes oi? also reducing the tendency ofresidual magnetism in the armature block and pole piece 5t to cause thearmature block l2 to stick to second pole piece 56 after the coil 5S hasbeen deenergized. Nor- (i5 mally, the hinge member ld; holds thearmature block in spaced relation to the second pole pieceas indicatedin Fig. 2. The hinge member la is secured against the opposite surfaceof the arinah ture block 12, and disposed against the other 0 surface ofthe armature engaging end of the hinge M is a small block or piece ofinsulating material 82, such as liber. A resilient contact f carryingmember Sliis secured against said piece of insulating material 82 andanother `piece of insulating material 86 is disposed against the outersurface of exible contact carrying member Se. The shock absorbing membered, armature block i2, hinge member M, insulating material 82, flexiblecontact carrying member 8s, and second insulating material 36 aresecured together in laminated relationship by providing each with aplurality of series of transversely aligned apertures which receiverivets '33, the rivets being peened at one end to secure all of thesecomponente in assembled relationship as illustrated in Fig. 7.

In order that the Contact carrying member lill may be electricallyinsulated from the assembly, the apertures 9i? therein which receive therivets :i8 are larger than the diameter of the stems of the rivets so asto prevent electrical engagement between said rivets and theperiine'ters oi said apertures. However, the contact carrying ineinber34 is provided at one end with a laterally extending nger 92 which isreceived in one of a pair of notches 94 provided in opposed edges of thesecond piece of insulating material B5 and, parallel to but spaced fromthe finger 92, there is another ringer Sli which is received in. theother notch Qa, whereby the contact carrying 'member Sil will at alltimes be aligned relative to the armature assembly in such a manner asto pre vent engagement between the perimeters or its apertures il@ andthe rivets 88. The finger 96 also provides means to which one end of aflexible electrical conductor a8 may be connected, is clearly shown inFigs. 2, 5 and 7.

The contact carrying member Sil is provided with a `pair ofsubstantially parallel flexible fingers Hill which are provided on theirouter ends with projections H32 which extend toward cach other, therebeing a space between the outer ends of the projections, however.Secured to each. projection lili is one of a pair of movable contacts|94 which may be formed, for example, by bending small pieces of silveror silver alloy into U-formations around said projections, asillustrated in Figs. i and S, so as to be xed to said extensions. Fromthe various figures, and particularly Fig. '7, it will be seen that eachpair ot rnovable contacts ills is movable between engaging positionswith a pair of the spaced fixed contacts 35 and 3S and engagementbetween said ixed and movable contacts takes pla-ce substantially alonga straight line parallel to the longitudinal axis of the terminalconductors 2li. liuc to the resiliency of the lingers lil@ and the factthat the extent of movement of the armature blocks l2 is greater thanthat required to merely move the movable contacts liil into contactingengagement with the fixed contacts Eli or 38. movable contacts will bemoved by each armature into firm engagement with the fixed contacts 3Bor 38 and in such a way that thc projections lll?. which support themovable contacts les will be iiexed along axes coaxial with the mainaxes of the armature assembly so as to produce a wiping engagementbetween the movable contacts i534 and the fixed contacts Sii or 33.

rEhe end of each hinge member 'it remote 'from the armature block l2 isprovided with, a slot H55, said slot receiving a screw 5&8 which isthreaded into one of a plurality of projections l il) which extendradially from collar i l2 mounted adjacent the outer end of pole piecemember and secured thereagainst by a head l lll comprising an enlargedouter end on mounting pin d2. Said head lifl thus serves to maintain inassembled relationship all of the above-described elements andcomponents surrounding the pin 42 and supported thereby in fixedrelationship to the base l2.

The iiexibility with which each hinge member 'M supports its armatureblock l2 relative to the free end of its iirst pole piece S6 isdetermined by the size of an opening H6 formed in each hinge member, asclearly shown in Fig. 6, and the size of said opening may be varied tosuit desired operating conditions. Also, the amount of flux required tosaturate the pole pieces 66 and the armature blocks 'I2 is determined,respectively, by forming apertures H8 and 20 therein. The sizes of theapertures IIB and l2@ in said first pole pieces and armature blocks maybe varied and the adjusting screws l 08 associated with each armatureassembly may also be regulated to vary the tension exerted by hingemember 'M so that, when the coil 53 is energized, the armature blocks T2of the various relay switch units will operate in a predeterminedsequence so as to cause, for example, the movable contacts I 04 of eacharmature assembly to move in such sequence` from engagement with xedcontact 36 into engagement with fixed contact 38 of its relay unit. Ifcurrent of sufiicient magnitude is supplied to said coil 53, theengagement of all of the armature blocks l2 with their respective secondpole pieces 56 will be very rapid and substantially simultaneous.However, the engagement of the armature blocks with their respectivepole pieces 56 can nevertheless be made to occur in accordance with apredetermined sequence if the adjustment means described above have beenregulated to produce a predetermined desired sequence.

Each relay unit in the exemplary construction of the inventionillustrated herein comprises three terminal conductors 24, as will beseen especially from Fig. 4, wherein the conductors of each unit areincluded within a bracket adjacent the periphery of the casing Ill shownin said ligure. Two of said terminal conductors of each unit aredisposed parallel to each other and slightly spaced apart in a directionradial to the pin 42. inner ends of each of said terminal conductorscarry, respectively, the fixed contacts 3 and 38. The third terminalconductor 2li has connected to its inner end one end of the flexibleconductor 98 which is secured at its other end to the linger 9E ofmovable contact carrying member 8d. Also supported by the base I2 is apair of additional terminal conductors 22 to which the ends of the coilleads are respectively connected.

From the foregoing, it will be seen that the arrangement of the armatureassemblies is such that, when the coil 58 is deenergized, the inherentresilient force of the hinge members 'I4 is such that it will hold thearmature block 12 attached thereto in spaced relation to its associatedsecond pole piece 56, whereby the movable contacts |04 will engage theradially outermost fixed contact 36 of its relay unit. When the coil 58is energized, the armature blocks 'l2 are moved in pre determinedsequence into engagement with the second pole pieces 55 and thus causethe movable contacts |04 carried thereby into engagement with theradially innermost xed contact 35 of their respective relay unit.

It will also be seen from the foregoing that the arrangement of thevarious components of each relay unit and also of the disposition of therelay units in circumferentially spaced relationship around the core andcoil of the solenoid assembly results in an extremely compactarrangement The accommodating either a single relay unit or asubstantial number of such relay units, as desired. Further, by directlyattaching the iixed contacts 36 and 38 directly to the inner ends oftheir terminal conductors 24, which are immediately adjacent the innersurface of the base I2, further compactness of arrangement is affordedwhile providing sufiicient space to permit the utilization of relativelylarge stationary contacts, whereby relatively large amperage loads maybe accommodated. The arrangement embodied in the relay comprising thepresent invention is such that it may be readily used with either D. C.or A. C. and embodiments of the invention which have been constructedand used successfully have employed as high as 400 cycle A. C. If A. C.is used in conjunction with relay units such as illustrated anddescribed herein, it is preferable to utilize a shading coil relative tothe second pole pieces 5B, but this may be readily accomplished forexample, by substituting several copper laminae 54 for several of theiron ones. Also, using fixed contacts 36 and 38 which have substantiallycylindrical outer surfaces permits the rotation of said contacts abouttheir axes to present unused operating surface portions to the movablecontacts |04 without requiring replacement of the xed contacts 36 and38. Still further, the shape of the perimeter of the base l2 is suchthat the band ill thereof may be readily sealed within the open end ofcup-shaped housing l0 by soldering or otherwise, where it is desiredthat the interior of the housing is to be provided with either anevacuated atmosphere or illled with inert gas to reduce arcing betweenthe xed and movable contacts. Still another advantage of the presentconstruction lies in the fact that the entire assembly comprisesrelatively few movable parts, thus minimizing wear between said parts.

While the invention has been illustrated and described in its preferredembodiment and has included certain details, it should be understoodthat the invention is not to be limited to the preoise details hereinillustrated and described since the same may be carried out in otherways, falling within the scope of the invention as claimed.

I claim:

l. A multiple relay comprising in combination, a core, a coilsurrounding said core, a pole member connected to one end of said coreand having a series of pole arms circumferentially spaced around saidcoil, a series of pole pieces correspending in number to said pole armsprojecting radially from the other end of said core and spaced at theirends from said pole arms, an elongated flexible member extending alongeach pole arm and at one end engaging and projecting beyond the endthereof, the other end of said member being spaced from said pole arm,an armature connected to the projecting end of each flexible member andpivotally supported thereby relative to the end of said pole arm formovement to and from engagement with one of said pole pieces, a movablecontact carried by each armature, and a screw associated with said otherend of each flexible member and adjustable to vary the tension exertedby said arm to resist movement of the armature thereon toward its polepiece, whereby said armatures may be regulated to move into engagementwith said pole pieces in a predetermined sequence when said coil isenergized.

2. In a multiple relay, the combination of a base, electrical insulatingmeans carried by said base, a magnet core supported by and extendingperpendicularly from said base, a coil surrounding said core, aplurality of first pole pieces ccnnected to said core and extendingradially from the outer end thereof and then bent to extend toward saidbase in parallel relation to each other and said core, a plurality ofsecond pole pieces corresponding in number to said iirst pole pieces andaligned therewith axially of said core, said second' pole piecesextending radially from said core adjacent the-end of the coil nearestsaid base, an elongated flexible member overlying the portion of eachfirst pole piece parallel to the core and extending beyond the free endthereof, an armature fixed to the extending portion ci each flexiblemember and supported thereby ad jacent the free end of said rst polepiece for limited pivotal movement toward and from said second polepiece axially aligned therewith, a housing connected to said base andenclosing the components of said multiple relay, a group of threeterminal conductors extending through the insulating means of said basefor each pair of aligned first and second pole pieces, a stationarycontact fixed directly to the inner end of two of each group of saidconductors and spaced from each other, a contact carried by eacharmature and disposed between said iixed contacts for movement by saidarmature between positions of engagement with said fixed contacts whensaid coil is energized and deenergized, and means electricallyconnecting the inner end of said other conductor of each group and themovable contact associated therewith.

3. In a relay, the combination of a base, a magnet core supported by andextending perpendicularly from said base, a coil surrounding said core,a pole arm connected to the outer end of said core and extendingparallel thereto toward said base adjacent the outer surface of saidcoil, a pole piece extending radially from said core adjacent the end ofsaid coil nearest said base, an elongated flexible member extendingalong said pole arm and at one end engaging and projecting beyond theend thereof, the other end of said member being spaced from the otherend of said pole arm, an armature connected to the projecting end ofsaid fiexible member and supported thereby adjacent the free end of saidpole arm for pivotal movement toward and away from said pole piece,means engaging the spaced end of said exible member and operable to varythe spacing thereof from said pole arm, a fixed contact supported bysaid base and extending toward said armature, and a contact carried bysaid armature and movable thereby to and from engagement with said fixedcontact.

4. In a relay, the combination of a base, a magnet core supported by andextending perpendiculariy from said base, a coil surrounding said core,a pole arm connected to the outer end of said core and extendingparallel thereto toward said base adjacent the outer surface of saidcoil, said pole arm having along and intermediate the ends of opposededges thereof an elongated notch, a pole piece extending radially fromsaid core adjacent the end of said coil nearest said base, an elongatedflexible member extending along said pole arm and at one end engagingand projecting beyond the end thereof, the other end of said memberbeing spaced laterally from the other end of said pole arm and securedagainst movement in a direction away from said pole arm, a flangeextending from each of the opposite edges of said flexible member anddisposed respectively in the notches in the opposed edges of said polearm to position said member relative to said arm, an armature connectedto the projecting end of said flexible member and supported therebyadjacent the freeend of said pole arm for pivotal movement toward andaway from said pole piece, a fixed contact supported by said base, and acontact carried by said armature and movable thereby to and fromengagement with said fixed contact.

5. In a relay, the combination oi' a solenoid assembly including anadjustable flexible member supporting an armature for movement relativeto the poles ef the solenoid when the solenoid is energized, a pair ofparallel flexible fingers extending from said flexible member, a movablecontact fixed to each'nger, said contacts being slightly spaced fromeach other in a direction transverse to said fingers, and a stationarycontact wider than the space between said movable contacts andengageabie by said movable contacts when said solenoid assembly isenergized, such movement of said movable contacts being` slightlygreater than necessary to effect contacting engagement between saidmovable and stationary contacts, whereby upon engagement of said fixedand movable contacts said fingers are flexed to cause said movablecontacts to engage said stationary contact with a yieldable wipingaction.

6. In a relay, the combination of a solenoid assembly including anadjustable flexible member supporting an armature for movement relativeto the poles of the solenoid when the solenoid is energized, a pair ofspaced parallel flexible fingers extending from the iiexible member,flexible projections extending transversely toward each other from theouter ends of said lingers, a contact fixed to the end of eachprojection and movable therewith when actuated by said armature, saidmovable contacts being slightly spaced from each other and extending ina direction substantially parallel to said fingers, and a stationarycontact wider than the space between said movable contacts andengageable by said movable contacts when said armature is moved by saidsolenoid assembly, said fixed contact having a cylindrical externalsurface substantially axially parallel to said arms and the movement ofsaid movable contacts by said armature being slightly greater thannecessary to eect contacting engagement between said movable andstationary contacts, whereby upon engagement between said iixed andmovable contacts said projections are flexed and cause said movablecontacts to engage said stationary contact in parallel relationship witha yieldable wiping action.

'7. In a relay, the combination of a housing having an opening, a baseconnected to and closing said opening in said housing, electricalinsulating means carried by said base, a solenoid assembly iixed to saidbase and including an adjustable flexible member carrying an armaturefor pivotal movement relative to the poles of the solenoid when thesolenoid is energized, a pair of cylindrical terminal conductorsextending through the insulating means of said base and supportedthereby, a stationary contact having a cylindrical external surfacecoaxial with and fixed directly to the inner end of one of saidconductors, a contact carried by the exible member and movable therewithre1- ative to said fixed contact when said solenoid is energized, saidmovable contact being substantially parallel to the cylindrical surfaceof said fixed contact when in engagement therewith and said terminalconductor supporting said stationary Contact being rotatable relative tosaid base to permit presenting to said movable Contact an unused portionof the external sur face of said stationary contact, and electricalconducting means extending between the inner end of said other conductorand said contact on said armature.

BERTIL S. BENGTSSON.

References Cited in the file 0f this patent UNITED STATES PATENTSNumber` Cil Number 12 Name Date Seasongood et a1. Mar. 15, 1932 ReynoldsApr. 15, 1941 Creveiing Jan. 5, 1943 Ebert Dec. 25, 1945 Reynolds Mar.22, 1949 Kuhn June 28, 1949 Spiro July 12, 1949 Wood Feb. 13, 1951McBerty et al. June 26, 1951

